Frame assembly and environmental enclosure

ABSTRACT

A frame assembly for an environmental enclosure including a plurality of channel-shaped members each including an end wall, opposed spaced side walls and an opening opposite the end wall adapted to receive and retain an end cap for retaining a film over the frame assembly having an integral internal channel which receives a connector element for interconnecting the frame members into a rectangular frame assembly and the frame assemblies are then interconnected to form an environmental enclosure. In one embodiment, the channel-shaped frame members include a generally L-shaped connector portion integral with one of the side walls for interconnecting the frame assemblies in side to side and end to end relation. In the other embodiment, the rectangular frame assembly has a height equal to the height of the environmental enclosure and transverse bracing elements having a U-shaped connector plate including transverse slots received in the internal channel.

RELATED APPLICATION

This application claims priority to Provisional Patent Application Ser. No. 60/579,410 filed in the U.S. Patent and Trademark Office on Jun. 14, 2004.

FIELD OF THE INVENTION

This invention relates to an environmental or contaminant shield or enclosure which prevents airborne contaminants from contacting a part received within or transmitted through the environmental or contaminant enclosure. More particularly, this invention relates to a frame assembly for an environmental or contaminant shield or enclosure and the shield or enclosure.

BACKGROUND OF THE INVENTION

Environmental or contaminant shields or enclosures, commonly referred to as “clean tunnels,” are utilized by many industries to prevent airborne contaminants from contacting a part received within or transmitted through the environmental or contaminant shield or enclosure. Such enclosures are used, for example, in an automotive paint facility, wherein the vehicle body is conveyed through clean tunnels between the several steps performed in the paint shop including, for example, sanding, tack-off (typically performed by feather dusters), paint booths and ovens to prevent airborne contaminants, including particulate and waterborne contaminants, from contacting the vehicle body following sanding, cleaning, tack-off and painting. A typical automotive paint facility may include over a mile of clean tunnels. As will be understood, however, other manufacturing and assembly facilities also use clean tunnels or enclosures during assembly or manufacture, including downtime. A typical clean tunnel or enclosure includes a frame assembly comprised of like channel-shaped frame members formed from sheet metal, typically steel, each having an open end, including an end or bottom wall and opposed side walls having opposed inwardly projecting end portions, wherein an end cap is received in the opening end of the channel-shaped frame members which secures a flexible film stretched over the frame members forming the clean tunnel as disclosed, for example, in U.S. Pat. Nos. 4,860,778 and 5,906,078.

As disclosed in such patents, the like channel-shaped frame members are then interconnected in end to end relation into a rectangular frame and the flexible sheet is stretched over the frame members and the rectangular frame members are then interconnected in side to side or end to end relation to form a U-shape clean tunnel or enclosure, preventing airborne contaminants from contacting a part received in the clean tunnel or enclosure. In a typical application, the frame members are first interconnected in end to end relation to form a rectangular frame, a flexible film is stretched over the rectangular frame and secured by end caps and the rectangular frame members with the flexible film are then interconnected in end to end and side to side relation with fasteners or clips. However, because the open ends of the channel-shaped frame members are closed by the end caps which secure the flexible film, assembly of the rectangular frame members with the end caps and flexible film require special clips or fasteners which penetrate the channel-shaped frame members making assembly of the frame members difficult, requiring special tools or parts and potentially reducing the structural integrity of the frame assembly.

It would also be desirable to easily remove and replace damaged flexible film after assembly, which comprises a majority of the surface area of the clean tunnel or enclosure, without special tools and to form the frame members from extruded aluminum to form a light weight, more rigid rugged construction. The environmental enclosure and frame assembly of this invention solves the problems associated with the prior art described above, including frame members which may be easily and securely assembled and wherein the flexible film may be easily assembled on the frame members or removed and replaced if damaged.

SUMMARY OF THE INVENTION

The frame assembly for an environmental enclosure of this invention includes a plurality of interconnected channel-shaped frame members, wherein each of the frame members includes a first end wall, opposed spaced side walls extending generally perpendicular to and integral with the first end wall and an opening opposite the first end wall adapted to receive and retain an end cap for retaining a film over the frame assembly. As thus far described, the channel-shaped frame members may be generally similar to the frame members disclosed in the above-referenced U.S. patents. However, the frame members of this invention further include an integral internal retainer channel within the channel-shaped frame members including a retainer wall integral with and extending generally perpendicular to one of the side walls, spaced from the end wall, for receiving a connector element interconnecting the channel-shaped frame members into a rectangular frame or for interconnecting abutting transverse frame members for braces or the like. In a preferred embodiment, the internal retainer wall is generally L-shaped, including a first portion integral with and extending generally perpendicular to the side wall and an end portion extending toward the first end wall of the channel-shaped frame member and in the disclosed embodiment, the first end wall further includes an internal retainer wall extending toward the end portion of the generally L-shaped retainer wall, forming an integral internal channel for receiving a retainer element as described. In a preferred embodiment, the channel-shaped frame members are formed from extruded aluminum, forming a light weight rigid construction.

In one of the disclosed embodiments of the channel-shaped members, the first side wall which includes the internal retainer channel, has a second end wall extending from and integral with the first side wall and the opening which receives the end cap is adjacent the second side wall and the opening is defined by parallel enlarged bead-shaped portions to receive and retain the end cap which retains a film overlying the frame assembly. In the other disclosed embodiments, the end portions of the side walls are U or hook-shaped each having an enlarged bead-shaped portion extending toward the first end wall.

In one of the preferred embodiments of the frame assembly of this invention, the channel-shaped frame members further include an L-shaped retainer portion including an end wall portion integral with a side wall, preferably a side wall opposite the integral internal channel described above, extending parallel to the first end wall and preferably aligned with the first end wall, and an end portion integral with and extending generally perpendicular to the end wall portion of the retainer portion forming a channel-shaped retainer or connector portion for interconnecting adjacent channel-shaped members in side to side relation, wherein the channel-shaped frame members of the frame assembly include a first plurality of channel-shaped members each having a generally L-shaped connector portion extending from one side wall and a second plurality of channel-shaped members which are a mirror image of the first channel-shaped members, and wherein the L-shaped retainer portions are aligned in side to side abutting relation and a fastener interconnects the first and second channel-shaped members.

The channel-shaped frame members of this invention are first assembled into rectangular frame assemblies, wherein the ends are preferably mitered or cut at a 45 degree angle and an L-shaped connector element having a first leg portion is received in the internal retainer channel of one frame member and a second leg portion is received in an internal channel of a perpendicular second channel-shaped frame member forming a rectangular frame assembly. The rectangular frame assembly is then covered with a thin, preferably transparent film and secured by end caps, such that each rectangular frame assembly is covered by a thin transparent film. In the disclosed embodiment of the frame assembly of this invention having a generally L-shaped retainer portion, the rectangular frame assemblies are then secured in side to side relation by a fastener, such as a clip, rivet or the like. In a preferred alternative embodiment, the frame assemblies are interconnected in side to side relation by a U-shaped retainer member having end portions received around the adjacent channel-shaped frame members and secured by suitable fasteners, such as screws, bolts, or the like. The frame assemblies may be rectangular or square. In one preferred embodiment, a rectangular frame assembly is first formed having a height equal to the desired height of the environmental enclosure and the rectangular frame assemblies include cross members having end portions secured to the rectangular frame assembly by U-shaped retainer members received within the cross members having slots received in the opposed end portions of the internal retainer channel, forming a light weight rigid assembly. The preferred alternative embodiment of the frame assembly has the advantage that the frame assembly is more rigid and does not require mirror image channel-shaped frame members and is thus less expensive to manufacture and assemble.

In a preferred embodiment of the frame assembly of this invention, the channel-shaped frame members are extruded, preferably extruded aluminum, forming a rigid lightweight frame assembly which is easily assembled or disassembled, as required. Further, the thin flexible film may be easily secured to or replaced on the frame assemblies by end caps which, in a preferred embodiment, includes a planar end portion and projecting generally parallel outwardly bowed legs which are received between the parallel enlarged bead-shaped portions defining the opening to the channel-shaped frame members, securely retaining the flexible film.

As will be understood, the disclosed embodiments of the frame assembly and channel-shaped frame members is provided for illustrative purposes only and various modifications may be made to the frame assembly and channel-shaped frame members within the purview of the appended claims as described further below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of one embodiment of an environmental enclosure of this invention;

FIG. 2 is a partial exploded view of the ends of two frame members, a connector channel, end caps and flexible film illustrating the assembly of the frame members shown in FIG. 1 in end to end relation;

FIG. 3 is a side view of a rectangular frame assembly, which is a component of the environmental enclosure shown in FIG. 1;

FIG. 4 is a side cross-sectional view of FIG. 3 in the direction of view arrows 4-4 with the end cap and film;

FIG. 5 is a partially exploded top perspective view of two rectangular frame assemblies shown in FIG. 1 illustrating one means of interconnecting the frame assemblies further illustrated in FIG. 6;

FIG. 6 is an end cross-sectional view of two frame members shown in FIG. 1 interconnected in side to side relation;

FIG. 7 is a side cross-sectional view similar to FIG. 5 with an alternative fastener interconnecting the frame members;

FIG. 8 is a partial side view of an alternative embodiment of the environmental enclosure of this invention;

FIG. 9 is a partial side cross-sectional view of FIG. 8 in the encircled area 9;

FIG. 10 is a cross-sectional view of FIG. 9, in the direction of view arrows 10-10;

FIG. 11 is a perspective view of one embodiment of the corner connector element illustrated in FIGS. 9 and 10;

FIG. 12 is a partial side cross-sectional view of FIG. 8 in the direction of view arrows 12-12;

FIG. 13 is an end cross-sectional view of FIG. 8 in the direction of view arrows 13-13;

FIG. 14 is a side cross-sectional view of FIG. 8 in the encircled area 14;

FIG. 15 is as end cross-sectional view of FIG. 14 in the direction of view arrows 15-15;

FIG. 16 is a perspective view of the connector element shown in FIGS. 14 and 15; and

FIG. 17 is an end cross-sectional view of FIG. 8 in the direction of view arrows 17-17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As will be understood, the embodiments of the frame assembly and environmental enclosure of this invention disclosed in the figures are for illustrative purposes only and various modifications may be made to the frame assembly and environmental enclosure of this invention with the purview of the appended claims as described further below.

The embodiment of the environmental enclosure or clean tunnel 20 shown in FIG. 1 and FIGS. 2 to 7 includes a plurality of interconnected rectangular frame assemblies 24 interconnected in side to side relationship, each including four frame members 26 or 26A interconnected in end to end and side to side relation having a flexible film 28 preferably stretched between the frame members 26 and 26A. The flexible film 28 may be formed of any suitable material, including a transparent polymeric film, such as polyethylene, having a thickness of for example about 0.18 mm and preferably formed of a polymer, such as polyethylene or a polyethylene resin which shrinks upon heating, such that the flexible film 28 may be stretched between the frame members 26 and 26A when heated, providing a smooth and regular surface. As will be understood, the shape or configuration of the environmental enclosure or clean tunnel 20 will depend upon the application of the environmental enclosure. For example, the environmental enclosure 20 may be in the form of a clean tunnel, as shown in FIG. 1, for enclosing a conveyor (not shown) for conveying a vehicle body (not shown) between the various work stations in a paint shop and may include access doors 30. Alternatively, the environmental enclosure 20 may be in the form of a housing having closed ends (not shown) for storage of manufactured parts in a manufacturing facility to prevent contamination of the parts prior to subsequent manufacturing operations. The disclosed embodiment of the environmental enclosure 20 and frame assembly of this invention may be sufficiently rigid to be a free standing structure supported by the floor or may include additional reinforcement (not shown in FIG. 1) again depending upon the application.

FIG. 4 is a cross-section of one preferred embodiment of a channel-shaped frame member 26 which includes a channel-shaped portion 32 and an integral connector portion 34. The channel-shaped portion 32 includes a first end wall portion 36, a first side wall 38 extending generally perpendicular to and integral with the first end wall portion 36 and a second side wall portion 40 spaced from the first side wall 38 extending perpendicular to and integral with the first end wall portion 36 forming a channel-shaped portion 32 having an opening 39 opposite the first end wall 36 as shown in FIG. 4. In a preferred embodiment, the first side wall 38 includes an end portion 42 at or adjacent the opening 39 at the open end of the channel-shaped portion 32 extending toward the second side wall 40 and the second side wall 40 includes an end portion 44 extending toward the first side wall 38 for receiving and retaining an end cap 64 as described below. In one preferred embodiment, the second side wall 40 also includes a second end portion 46 extending away from the first end portion 44 and overlying the end wall 48 of the connector portion 34. The disclosed embodiment of the connector portion 34 includes an end wall portion 48 which is integral with the second side wall 40 and generally aligned or continuous with the first wall portion 36. The connector portion 34 further includes a leg portion 50 which is spaced from the second side wall 40 and preferably extends generally perpendicular to and is integral with the end wall portion 48 of the connector portion 34 as shown in FIG. 4. In a preferred embodiment, the leg portion 50 has a shorter length than the side walls 38 and 40 of the channel-shaped portion 32. In a preferred embodiment of the frame members 26, the end portions 42, 44 and 46 include an enlarged bead-shaped cap retainer portion 52 which are generally parallel to the side walls 38 and 40 and extend toward the first end wall 36 and the end wall 48 of the connector portion, respectively, having an enlarged bead-shaped cross-section and an arcuate outer exterior surface to receive and retain end caps as described below.

As set forth below, the frame members 26 are preferably interconnected in end to end relation to form rectangular frame assemblies 24 as shown in FIGS. 1 and 3. In a preferred embodiment, the channel-shaped portion 32 of each of the frame members 26 includes an internal integral channel 55 configured to receive corner connectors 54, also shown in FIG. 2. In a preferred embodiment, the internal channels 55 include a generally L-shaped portion 56 integral with the first side wall 38 having an end portion 58 extending toward the first bottom portion 36 and the internal channel 55 may include a second wall portion 60 which extends generally perpendicular to and is integral with the first bottom wall portion 36 generally aligned with the end portion 58 of the generally L-shaped web portion 56, forming an integral internal channel 55 in the channel-shaped portion 32 having an opening opposite the second side wall 40 as best shown in FIG. 4. The generally L-shaped web portion 56 may also be arcuate or J-shaped to receive an arcuate corner connector channel 54. As discussed further below, the frame members 26 (and 26A described below) may be formed of aluminum and extruded forming a light weight relatively rigid structure at reduced cost. As shown in FIG. 3, the ends of the frame members 26 may be mitered or cut at a 45 degree angle, such that the abutting ends interfit as shown in FIG. 3 to form the rectangular frame assemblies 24 as best shown in FIG. 2. The corner connectors 54 in this embodiment are preferably L-shaped having leg portions 62 which are telescopically received in the internal channels 55 in the channel-shaped portions 32 of the frame members 26 to complete the assembly of the rectangular frame assemblies 24. The flexible film 28 may then be received over the inwardly projecting end portions 42 and 44 of the side walls 38 and 40, respectively, and secured in place by a first end cap 64 as shown in FIGS. 2 and 4. Alternatively, as described below, the entire frame assembly may be assembled before application of the flexible film 28 and end caps 64.

In one preferred embodiment, the first end caps 64 include a planar end portion 66 and projecting generally parallel outwardly bowed legs 68. As best shown in FIG. 4, the legs 68 may include an arcuate outer surface 70 and the distal ends 70 of the leg portions 68 may be bowed slightly outwardly to interfit with the arcuate cap retainer portions 52 of the end portions 42 and 44 of the side walls 38 and 40, respectively, to securely retain the flexible film 28. The first end caps 64 may be formed from an extruded polymer, such as polyethylene or polypropylene, and the flexible film 28 is preferably formed of a heat shrinkable polymer, such as polyethylene, and the flexible film 28 is then preferably heated following assembly to stretch the film 28 over the rectangular frame assemblies 24 and 24A.

Once the rectangular frame assemblies 24 and 24A are assembled, as described above, the embodiments of the rectangular frame members 24 and 24A may be interconnected in side to side relation by the connector portions 34, as now described, with reference to FIGS. 6 and 7. First, however, it should be noted from FIGS. 6 and 7 that the frame members include frame members 26 as just described and frame members 26A which are substantially a mirror image of the frame members 26, but may be otherwise identical. That is, the frame members 26A may be identical to the frame members 26 except that the channel-shaped connector portion 32A is on the right in FIGS. 6 and 7 and the connector portion 34A is on the left in FIGS. 6 and 7, whereas the channel-shaped portion 32 of frame member 26 is on the left in FIGS. 6 and 7 and the connector portion 34 of frame member 26 is on the right in FIGS. 6 and 7. Thus, no further description of the frame members 26A is required for a complete understanding and the elements of the frame members 26A are numbered the same as the frame members 26 with the suffix “A.” The rectangular frame assemblies 24 and 24A formed from the frame members 26 and 26A are then assembled in side to side abutting relation as shown in FIGS. 6 and 7, with the leg portions 50 and 50A of the connector portions 34 and 34A in abutting relation and the leg portions are then secured together by suitable fasteners.

In an embodiment of the frame assembly shown in FIGS. 5 and 6, the rectangular frame members 24 are retained by a U-shaped clip 74 having parallel leg portions 76 received over the leg portions 50 and 50A of the frame members 26 and 26A, respectively, retaining the rectangular frame members 24 and 24A in side to side abutting relation. The U-shaped clips may be formed of a metal, such as aluminum, but are preferably formed of a relatively rigid extruded plastic, such as polypropylene. The frame assembly shown in FIG. 6, may thus be assembled without tools or skilled labor. As will now be understood, the leg portions 50 and 50A preferably have a length less than the length of the side walls 38, 40, 38A and 40A to provide easy access to the connector portions 34 and 34A, respectively, for securement of the frame members 24 and 24A together as described. FIG. 5 also illustrates the assembly of two rectangular frame members 24 and 24A with the U-shaped clip 74, wherein the leg portions 50 and 50A are first aligned and moved into abutting relation and the U-shaped clip 74 is then received over the abutting leg portions 50 and 50A. FIG. 7 illustrates an alternative means of securing the leg portions 50 and 50A using conventional rivets 78 received through openings 80 in the abutting leg portions 50 and 50A. The assembly of FIG. 7 is otherwise identical to the assembly shown in FIG. 6 and thus no further description is required.

The embodiment of the frame assemblies shown in FIGS. 6 and 7 may then be finished and sealed with second end caps 82, which are identical to the first end cap 64, except for size. That is, the second end caps 82 include a planar end portion 84 and generally parallel outwardly bowed legs 86 which are received between the opposed second end portions 46 and 46A of the second side walls 40 and 40A, respectively, as shown in FIGS. 5, 6 and 7. Although the second end caps 82 are optional, they prevent the accumulation of dust or debris in the connector portions 34 and 34A and provide a more finished assembly.

It is important to note that the embodiment of the frame assembly of this invention shown in FIG. 1 and the frame assemblies described below may be assembled before application of the film 28 which would be difficult, if not impossible, with the frame assemblies for environmental enclosures disclosed in the above referenced prior art. That is, the channel-shaped frame members 26 may first be assembled into rectangular frame assemblies 24, as described above, and the rectangular frame assemblies may then be assembled into an enclosure, such as the clean tunnel 20 shown in FIG. 1, before application of the flexible film 28. This is an important advantage over the prior art because the flexible film 28 may be damaged during assembly. Following assembly of the rectangular frame assemblies 24 and 24A, the flexible film 28 is cut to size and applied over the opposed end portions 42 and 44 or 42A and 44A, and secured in place by the first end cap 64 and preferably heated to stretch the film in place over the rectangular frame assemblies 24 and 24A. This is a particular advantage where the flexible film 28 is transparent because this method of assembly provides a clear view of the interior of the environmental enclosure 20. Further, the clear film may be damaged or coated with debris during use and the configuration of the frame members 26 and 26A makes replacement of the flexible film easy and simple without requiring tools. The first end caps 26 are simply removed and the flexible film 28 may be easily replaced. It is also important to note that the frame assemblies of this invention may also be easily disassembled and changed or stored without special tools, particularly where the rectangular frame assemblies are secured in side to side relation with a clip, such as shown at 74 in FIG. 6.

The alternative preferred embodiment of the environmental enclosure or clean tunnel 120 shown in FIG. 8 also includes a plurality of interconnected frame assemblies 124 interconnected in side to side relation as described below and the rectangular frame members 124 are covered with a flexible film 128 which is preferably stretched over the frame assemblies as described above. However, in this embodiment of the environmental enclosure 120, the rectangular frame members 124 preferably have a height equal to the desired height of the environmental enclosure and may include cross members 122 for rigidity as described below. As set forth above, the shape or configuration of the environmental enclosure 20 will depend upon the application of the environmental enclosure. The embodiment of the rectangular frame assemblies 124 shown in FIG. 8 are formed from a plurality of channel-shaped frame members 132 best shown in cross-section in FIG. 10.

As shown in FIG. 10, this embodiment of the channel-shaped members 132 each include a first end wall 136 and opposed first and second side walls 136 and 138 which are preferably integral with and extend generally perpendicular to the first end wall 136. The channel-shaped members 132 further include an opening 139 opposite the first end wall 136 for receipt of an end cap 164 as described above. In this embodiment, however, the end portion or second end wall 142 of the side wall 138 opposite the first end wall 136 extends to the opening 139, such that the opening 139 is spaced from the integral internal retainer channel 155 formed by the generally L-shaped wall 156 integral with the first side wall 138 and the wall 160 integral with the first end wall 136. As described above, the end portion 158 of the L-shaped internal wall 156 preferably extends toward the first end wall 136 and the end wall 136 further includes an integral internal wall 160 which extends toward the end portion 158, forming an integral internal channel 155 for receipt of a connector element 154 as described below. As also stated above, the L-shaped wall 156 may also be arcuate. In this embodiment of the channel-shaped frame members 132, the opening 139 opposite the first end wall 136 includes parallel enlarged bead-shaped portions 152 and 153 having an arcuate outer surface, wherein the bead-shaped portion 152 at the end of the second end wall 142 extends toward the first end wall 136 and the enlarged bead-shaped portion 153 at the distal end of the second side wall 140 extends inwardly from the second side wall 140 as shown in FIG. 10. As described above, a preferred embodiment of the end cap 164 includes a planar portion 166 and generally parallel outwardly bowed leg portions 168 having an outer surface 170 and bowed end portions 172 which are securely retained between the parallel bead-shaped end portions 152 and 153, securely retaining the flexible film 128. As will be noted, the elements of the channel-shaped frame members 132 are numbered in the same sequence as the channel-shaped frame members 32 for ease of understanding.

As described above, the rectangular frame assemblies 124 may be formed by mitering the ends of the channel-shaped frame members 132 at a 45 degree angle as shown in FIG. 9 and the connector element 154 is L-shaped, as best shown in FIG. 11 having perpendicular end portions 155 preferably including a plurality of teeth 157 outwardly inclined from the distal ends in a “Christmas tree” configuration to securely retain the leg portions 155 in the integral internal channels 155 formed by the L-shaped wall 156 integral with the first side wall 138 and an opposed wall 160 integral with the first end wall 136. The L-shaped connector element 154 may be an aluminum extrusion. As will be understood from the above description of the channel-shaped frame members 132, this embodiment of the frame members does not include an L-shaped integral connector portion 34, but this embodiment of the channel-shaped frame members 32 does not require a mirror image frame member as described above with reference to FIGS. 5 to 7 and thus results in less cost and a more rigid construction as described below.

FIG. 12 illustrates a suitable tie down of the environmental enclosure 120 to the floor 180, such as the concrete floor of a manufacturing facility. In the disclosed embodiment shown in FIG. 12, an L-shaped tie down plate having a horizontal portion 182 is affixed to the floor 180 by a conventional concrete anchor bolt 184 having a nut 186. The vertical leg 188 is attached to the first end wall 136 of the channel-shaped member 132 by a conventional machine screw 190 or the like, forming a rigid support for the environmental enclosure 120 shown in FIG. 8.

FIG. 13 illustrates a suitable interconnection between adjacent channel-shaped frame members 132 in side to side abutting relation with a U-shaped connector plate 192. As shown in FIG. 13, the U-shaped connector plate 192 includes a planar central portion 194 having a width slightly greater than the combined width of the first end walls 136 of two abutting channel-shaped frame members 132 and transverse leg portions 196 which receive the second side walls 140 of the channel-shaped frame members 132 and the central portion 194 is affixed to the first end wall 136 by machine screws 198 or the like.

FIGS. 14 and 15 illustrate a suitable connection between the vertical channel-shaped members 132 and the cross members 122 shown in FIG. 8. In a preferred embodiment, the cross members 122 are identical to the channel-shaped frame members 132 and the horizontal cross members 122 are attached to the vertical channel-shaped frame members 132 by a U-shaped connector plate 200 best shown in FIG. 16. The connector plate 200 includes a planar central portion 202 having opposed transverse slots 204 adjacent to but spaced from one of the perpendicular leg portions 206. As shown in FIG. 14, the central portion 202 of the U-shaped connector plate 200 is attached to the first end wall 136 of the vertical channel-shaped frame members 132 by machine screws 208 or the like. The transverse leg portions 206 of the U-shaped connector plate 200 are then received within the channel-shaped transverse brace member 122 and secured by machine screws 210. In the preferred embodiment, the leg portion 158 of the L-shaped internal channel portion is received in one slot 204 and the opposed internal wall 160 is received in the opposed slot forming a very rigid construction as shown in FIG. 15.

FIG. 17 illustrates a suitable interconnection between the top transverse frame member 132 of the rectangular frame assembly 124 and a channel-shaped frame member 212 of a rectangular frame assembly which forms the top of the environmental enclosure 120 generally as shown in FIG. 1. In a preferred embodiment, the channel-shaped frame member 212 is identical to the channel-shaped frame member 132 and the rectangular frame assemblies which form the top of the environmental enclosure (not shown) may be identical to the rectangular frame assemblies 124 described above. In the disclosed embodiment, the top channel-shaped frame member 132 is attached to the channel-shaped frame member 212 by an L-shaped connector plate 214 which is received against the first side wall 138 of the channel-shaped frame members 132 and 212 and secured in place by machine screws 214 or the like as shown in FIG. 17. As set forth above, the channel-shaped frame member 212 may be identical to the channel-shaped frame members 132 and thus the components of the channel-shaped frame member 212 are numbered the same as the components of the channel-shaped frame member 132 in FIG. 17. As shown in FIG. 17, the machine screws 214 are received through the integral internal channels 155 formed by the opposed walls 158 and 160 and the flexible film 128 secured by end caps 164 are located on the inside of the environmental enclosure.

As will be understood from the above description of the preferred alternative embodiment of the environmental enclosure 120 shown in FIGS. 8 to 17, the assembly of the environmental enclosure is similar to the environmental enclosure 20 shown in FIGS. 1 to 7. That is, the rectangular frame assemblies 124 may be first assembled, as described above, and the rectangular frame members may then be covered with a flexible, preferably transparent film 128 and secured by end caps 164. As described above, the flexible film 128 is then preferably heated to stretch the film over the rectangular frame assemblies 124 and the flexible film 128 may be easily replaced if damaged following assembly of the environmental enclosure. As set forth above, the embodiment of the environmental enclosure 120 and channel-shaped frame members 132, 202 and 212 have several advantages over the environmental enclosure 20 and channel-shaped frame members 26 described above, including reduced costs of manufacturing and assembly and increased rigidity. However, both embodiments provide important advantages over the prior art, including reduced weight, ease of assembly and easy replacement of the flexible film. As set forth above, the channel-shaped frame members may be formed from extruded aluminum making the environmental enclosure or clean tunnel 20, 120 light in weight and relatively rigid, but having sufficient flexibility for ease of assembly. The environmental enclosure or clean tunnel may be fixed directly to the floor, such as a concrete floor or steel platform using power actuated fastening systems, such as pins, anchor bolts or the like. The upper rectangular frame assemblies may also be supported by the building structure, using brackets, cables or the like.

As will be understood from the above description of the preferred embodiments of the frame assemblies and environmental enclosures of this invention, various modifications may be made within the purview of the appended claims. For example, the opening to the channel-shaped portion or channel-shaped members may be configured to receive other end caps as disclosed, for example, in the prior art. Further, any suitable fasteners may be utilized to interconnect the adjacent the channel-shaped frame members or the frame members to the connector plates described above., including machine screws, bolts or the like The frame assemblies shown in FIGS. 1 to 7 may be square, as shown, or rectangular with transverse bracing elements as disclosed in FIGS. 8 to 17. Finally, as described above, the environmental enclosure or clean tunnel of this invention may have any configuration depending upon the application. That is, the enclosure may include end walls at various locations and venting may be provided, as required. Having described alternative embodiments of the environmental enclosure, frame assemblies and channel-shaped frame members of this invention, the invention is now claimed as follows. 

1. A frame assembly for an environmental enclosure, comprising: a plurality of channel-shaped members, each channel-shaped member including a first end wall, opposed spaced side walls extending generally perpendicular to and integral with said first end wall, an opening opposite said first end wall adapted to receive and retain an end cap for retaining a film over said frame assembly, and an integral internal retainer channel including a wall integral and generally perpendicular to one of said side walls spaced from said first end wall forming an internal channel with said first end wall; and said plurality of channel-shaped frame members including a first channel-shaped frame member in abutting relation with a second channel-shaped frame member and a retainer element received in said internal channel of said first channel-shaped frame member interconnecting said first and second channel-shaped frame members.
 2. The frame assembly as defined in claim 1, wherein said retainer element includes a first leg portion received in said internal retainer channel of said first channel-shaped frame member and a second leg portion received in said internal retainer channel of said second channel-shaped frame member.
 3. The frame assembly as defined in claim 2, wherein said second channel-shaped frame member extends generally perpendicular to said first channel-shaped frame member and said retainer element is generally L-shaped.
 4. The frame assembly as defined in claim 1, wherein said first end wall of said plurality of channel-shaped frame members include an internal wall integral with and extending generally perpendicular to said first end wall extending toward said wall integral with and generally perpendicular to one of said side walls forming said internal channel.
 5. The frame assembly as defined in claim 1, wherein said wall integral with and generally perpendicular to one of said side walls is generally L-shaped including an end portion extending toward said first end wall.
 6. The frame assembly as defined in claim 1, wherein said opening opposite said first end wall includes opposed enlarged parallel bead-like portions at least one of which extends toward said first end wall adapted to receive and retain an end cap.
 7. The frame assembly as defined in claim 1, wherein one of said opposed spaced side walls include a U-shaped end portion.
 8. The frame assembly as defined in claim 7, wherein said U-shaped end portions of said opposed spaced side walls include an end portion extending toward said first end wall.
 9. The frame assembly as defined in claim 1, wherein said plurality of channel-shaped frame members each include an integral connector portion including an end wall integral with one of said opposed side walls extending generally parallel to said first end wall having an end portion extending generally perpendicular to said end wall of said connector portion spaced from said one of said opposed side walls forming an L-shaped connector portion, and said generally L-shaped connector portion of said first channel-shaped frame member engaging said generally L-shaped connector portion of a third channel-shaped frame member and a connector element interconnecting said generally L-shaped connector portions of said first and third channel-shaped members.
 10. The frame assembly as defined in claim 1, wherein one of said side walls includes an integral end portion extending toward an opposite side wall having a U-shaped portion extending toward said first end wall.
 11. A frame assembly for an environmental enclosure, comprising: a plurality of channel-shaped frame members, each of said channel-shaped frame members including a first end wall, opposed spaced side wall integral with and extending generally perpendicular to said first end wall, an opening opposite said first end wall having parallel sides adapted to receive and retain an end cap for retaining a film over said frame assembly, and an integral internal channel within said channel-shaped frame members including a first generally L-shaped internal channel wall portion integral with one of said side walls including a first portion integral with and extending generally perpendicular to said one of said side walls and an end portion extending toward said first end wall and a second internal channel wall integral with and extending generally perpendicular to said first end wall portion extending toward said second end portion of said first generally L-shaped internal wall portion.
 12. The frame assembly as defined in claim 11, wherein said frame assembly includes a first channel-shaped frame member in abutting relation with a second channel-shaped frame member and a retainer element in one of said internal channels within one of said first and second channel-shaped members interconnecting said first and second channel-shaped frame members.
 13. The frame assembly as defined in claim 11, wherein said connector element includes a first leg portion received in said internal channel of said first channel-shaped frame member and a second leg portion received in said internal channel of said second channel-shaped frame member interconnecting said first and second channel-shaped frame members.
 14. The frame assembly as defined in claim 13, wherein said leg portions of said connector element include a plurality of teeth forming an interference fit with said internal channels of said first and second channel-shaped frame members.
 15. The frame assembly as defined in claim 11, wherein said opening opposite said first end wall includes parallel enlarged bead-shaped portions for retaining an end cap in said opening.
 16. The frame assembly as defined in claim 15, wherein said side walls each include a U-shaped end portion having an said enlarged bead-shaped portion at an end of said U-shaped portions.
 17. The frame assembly as defined in claim 11, wherein said one of said side walls include a second end wall extending generally parallel to and opposite said first end wall defining said opening adjacent the other of said side walls.
 18. The frame assembly as defined in claim 17, wherein said opening is rectangular having parallel enlarged bead-shaped portions for retaining an end cap.
 19. The frame assembly as defined in claim 11, wherein each of said plurality of channel-shaped frame members includes an integral retainer portion including a first retainer wall portion integral with a side wall opposite said one of said side walls extending generally parallel to said first end wall and a second retainer wall portion integral and extending generally parallel to said first wall portion.
 20. A frame assembly for an environmental enclosure, comprising: a plurality of interconnected frame members, each of said frame members including a channel-shaped portion having a first end wall portion, opposed spaced side walls extending generally perpendicular to and integral with said first end wall portion defining an open end opposite said first end wall portion, said side walls having opposed inwardly projecting portions adjacent said open end adapted to receive and retain an end cap, and a connector portion integral with said channel-shaped portion including a second end wall portion generally aligned with said first end wall portion extending generally perpendicular to and integral with said second end wall portion spaced from an adjacent side wall portion; said plurality of interconnecting frame members including two frame members having abutting leg portions; and a fastener interconnecting said leg portions.
 21. The frame assembly as defined in claim 20, wherein said leg portion has a length less than said side walls.
 22. The frame assembly as defined in claim 20, wherein said two frame members are mirror images of each other.
 23. The frame assembly as defined in claim 20, wherein said inwardly projecting portions of said side walls are hook-shaped.
 24. The frame assembly as defined in claim 23, wherein said hook-shaped projecting portions are U-shaped each including a first portion extending generally perpendicular to said side walls and an end portion extending generally parallel to said side walls.
 25. The frame assembly as defined in claim 24, wherein said end portion of said hook-shaped portion has a greater thickness than said first portion and rounded end surfaces.
 26. The frame assembly as defined in claim 20, wherein said side walls include an outer side wall and an inner side wall adjacent said connector portion, and said inner side wall including an outwardly projecting end portion adjacent said open end overlying said second bottom wall portion, such that said two side frame members have opposed projecting end portions adapted to receive a second end cap.
 27. The frame assembly as defined in claim 20, wherein one of said side walls of said frame members includes an integral generally L-shaped web portion spaced from said first bottom wall portion having an end portion extending toward said first bottom wall portion, and said first bottom wall portion including an opposed web portion, wherein said web portions are adapted to receive an L-shaped connector interconnecting said frame members in end to end relation.
 28. A frame assembly for an environmental enclosure, comprising: a first plurality of frame members each including a channel-shaped portion having a first end wall portion, a first side wall extending generally perpendicular to and integral with said first end wall portion, a second side wall spaced from said first side wall extending generally perpendicular to and integral with said first end wall portion, said first side wall including an end portion extending toward said second side wall and said second side wall including an end portion extending toward said first side wall, and a connector portion including a second end wall portion integral with said second side wall generally aligned with said first end wall portion and a leg portion spaced from said second side wall extending generally perpendicular to and integral with said second end wall portion having a length less than said side wall; a second plurality of frame members each being a mirror image of said first plurality of frame members, each including a first end wall portion, a first side wall extending generally perpendicular to and integral with said first end wall portion, a second side wall spaced from said first side wall extending generally perpendicular to and integral with said first end wall portion, said first end wall portion including an end portion extending toward said second side wall, said second side wall including an end portion extending toward said first side wall and a connector portion including a second end wall portion integral with said second side wall aligned with said first end wall portion and a leg portion spaced from said second side wall extending generally perpendicular to and integral with said second end wall portion, wherein said leg portions of one of said first plurality of frame members and said leg portion of one of said second plurality of frame members are abutting; and a fastener interconnecting said leg portions of said one of said first plurality of frame members to said leg portion of said one of said second plurality of frame members.
 29. The frame assembly as defined in claim 28, wherein said end portions of said first and second side walls are hook-shaped adapted to receive and retain an end cap for securing a flexible film to said frame members.
 30. The frame assembly as defined in claim 29, wherein said hook-shaped portions of said side walls are U-shaped, including a first portion extending generally perpendicular to said side walls and an end portion extending generally parallel to said side walls.
 31. The frame assembly as defined in claim 29, wherein said hook-shaped end portions of said side walls have a greater thickness than said first portion, and rounded end surfaces.
 32. The frame assembly as defined in claim 28, wherein said first side wall of said first and second plurality of frame members includes an integral generally L-shaped web portion having an end portion extending toward said first bottom wall portion and said first bottom wall portion including an opposed web portion for receiving an L-shaped connector interconnecting said first and second plurality of frame members to a third plurality of frame members in end to end relation. 